Sida cordifolia L.: Ethnobotany, Phytochemistry, Phytonanotechnology, and Commercial Application.

BACKGROUND: After a period of prolonged indifference, where synthetic drugs were preferred, interest in the biological aspects and bioactive ingredients of plants accountable for therapeutic potential has been explored eminently. Sida cordifolia L. is a perennial herb that has been widely utilized in Indian (Ayurveda, Unani, and Siddha), American, and Chinese folk medicine and herbalism practice for curing a wide range of ailments in human beings. OBJECTIVE: The goal of this review is to elucidate indigenous knowledge parallelly with the pharmacotherapeutics potential of Sida cordifolia L. against various diseases. It is also intended to display pertinent information related to nanoparticle profiling. METHODS: In the current comprehensive study, web-based searches were performed by using several databases, such as Google Scholar, PubMed, ResearchGate, Science Direct, and Scopus, to figure out relevant research work and data published in academic journals from 1930 to July, 2023 using single or combination of keywords listed herewith. RESULTS: More than 50 chemical constituents, including quinazoline and phenethylamine alkaloids, flavones, flavonol, phytosterol, fatty acids, etc., were reported to be found in different parts of healthy plants. Apart from traditional claims and pharmacological aspects, several marketed herbal formulations and granted patents were also described. CONCLUSION: Several in-vitro and in-vivo studies validated the usage of S. cordifolia as antiinflammatory, antibacterial, antifungal, antiprotozoal, anthelmintic, anticancer, antiulcer, cardioprotective, hypoglycemic, etc. agent. Few patents are also related to S. cordifolia, and more research work needs to be carried out for its potential granted to use as an antiviral agent and other new drug discovery molecules.

Macrolactin A mediated biocontrol of Fusarium oxysporum and Rhizoctonia solani infestation on Amaranthus hypochondriacus by Bacillus subtilis BS-58.

Plant diseases are one of the main hurdles for successful crop production and sustainable agriculture development world-wide. Though several chemical measures are available to manage crop diseases, many of them have serious side effects on humans, animals and the environment. Therefore, the use of such chemicals must be limited by using effective and eco-friendly alternatives. In view of the same, we found a Bacillus subtilis BS-58 as a good antagonist towards the two most devastating phytopathogens, i.e., Fusarium oxysporum and Rhizoctonia solani. Both the pathogens attack several agricultural crops (including amaranth) and induce a variety of infections in them. The findings of scanning electron microscopy (SEM) in this study suggested that B. subtilis BS-58 could inhibit the growth of both the pathogenic fungi by various means such as perforation, cell wall lysis, and cytoplasmic disintegration in the fungal hyphae. Thin-layer chromatography, LC-MS and FT-IR data revealed the antifungal metabolite to be macrolactin A with a molecular weight of 402 Da. Presence of the mln gene in the bacterial genome further endorsed that the antifungal metabolite produced by BS-58 was macrolactin A. Pot trial conducted in the present study showed that seed treatment by BS-58 effectively reduced seedling mortality (54.00 and 43.76%) in amaranth, when grown in pathogen infested soil (F. oxysporum and R. solani, respectively), when compared to their respective negative controls. Data also revealed that the disease suppression ability of BS-58 was almost equivalent to the recommended fungicide, carbendazim. SEM analysis of roots of the seedlings recovered from pathogenic attack substantiated the hyphal disintegration by BS-58 and prevention of amaranth crop. The findings of this study conclude that macrolactin A produced by B. subtilis BS-58 is responsible for the inhibition of both the phytopathogens and the suppression of the diseases caused by them. Being native and target specific, such strains under suitable conditions, may result in ample production of antibiotic and better suppression of the disease.

Bioformulation Containing Cohorts of Ensifer adhaerens MSN12 and Bacillus cereus MEN8 for the Nutrient Enhancement of Cicer arietinum L.

Here we examine the effects of different carrier based bioinoculants on the growth, yield and nutritional value of chickpea and on associated soil nutrients. A consortium of two taxonomically distinct endophytic bacteria-Ensifer adhaerens MSN12 and Bacillus cereus MEN8-have promising plant growth promoting (PGP) attributes. We demonstrate their delivery from the laboratory to the field via the formulation of an effective bioinoculant with economic and accessible carriers. Sugarcane straw ash (SCSA) was found to be an efficient carrier and bioformulation for enhancing viability and shelf-life of strains up to 12 months. A bioformulation containing an SCSA-based consortium (MSN12 + MEN8) increased seed germination by 7%, plant weight by 29%, length by 17%, seed-yield by 12%, harvesting index by 14% and proximate nutritional constituents by 20% over consortium treatment without SCSA. In addition, the bioformulation of post-harvest treated soil improved the physico-chemical properties of the soil in comparison to a pre-sowing SCSA-based bioformulation treated crop, being fortified in different proximate nutritional constituents including dry matter (30%), crude protein (45%), crude fiber (35%), and ether extract (40%) in comparison to the control. Principal component analysis and scattered matrix plots showed a positive correlation among the treatments, which also validates improvement in the soil nutrient components and proximate constituents by T6 treatment (MSN12 + MEN8 + SCSA). The above results suggest efficiency of SCSA not only as a carrier material but also to support microbial growth for adequate delivery of lab strains as a substitute for chemi-fertilizers.

The changing paradigm of rhizobial taxonomy and its systematic growth upto postgenomic technologies.

Rhizobia are a diazotrophic group of bacteria that are usually isolated form the nodules in roots, stem of leguminous plants and are able to form nodules in the host plant owing to the presence of symbiotic genes. The rhizobial community is highly diverse, and therefore, the taxonomy and genera-wise classification of rhizobia has been constantly changing since the last three decades. This is mainly due to technical advancements, and shifts in definitions, resulting in a changing paradigm of rhizobia taxonomy. Initially, the taxonomic definitions at the species and sub species level were based on phylogenetic analysis of 16S rRNA sequence, followed by polyphasic approach to have phenotypic, biochemical, and genetic analysis including multilocus sequence analysis. Rhizobia mainly belonging to α- and ß-proteobacteria, and recently new additions from γ-proteobacteria had been classified. Nowadays rhizobial taxonomy has been replaced by genome-based taxonomy that allows gaining more insights of genomic characteristics. These omics-technologies provide genome specific information that considers nodulation and symbiotic genes, along with molecular markers as taxonomic traits. Taxonomy based on complete genome sequence (genotaxonomy), average nucleotide identity, is now being considered as primary approach, resulting in an ongoing paradigm shift in rhizobial taxonomy. Also, pairwise whole-genome comparisons, phylogenomic analyses offer correlations between DNA and DNA re-association values that have delineated biologically important species. This review elaborates the present classification and taxonomy of rhizobia, vis-a-vis development of technical advancements, parameters and controversies associated with it, and describe the updated information on evolutionary lineages of rhizobia.

Appraisal of biofilm forming bacteria in developing buffalo dung-based bioformulation coupled to promote yield of Foeniculum vulgare Mill.

Chemical fertilizers impart deleterious effects on crop productivity and its nutrients which is a serious concern among agriculturist. Current research focuses on the commercial preparation of an eco-friendly and cost-effective bioformulation using buffalo dung slurry and beneficial plant growth-promoting (PGP) and biofilm forming strains. 40 strains were isolated from buffalo dung showing PGP activities. Among them, 03 strains were further selected to sequence by 16S rRNA technology and identified as Pseudomonas aeruginosa BUFF12, Proteus mirabilis BUFF14, Enterobacter xiangfangensis BUFF38. The strains were used for consortium preparation on the basis of increase in PGP activity. The consortium of strains increases in vitro PGP attributes at different percentage, i.e., 22% increase in IAA production, 10% increase in siderophore production, 5% increase in P- solubilization, 8% increase in K- solubilization, and 11% increase in S-oxidation. Three carrier materials, i.e., molasses of sugarcane, rice gruel, and buffalo dung slurry, were chosen to conduct the study. Among them, dung slurry proved to be an effective supportive material on the basis of their physico-chemical analysis and viability of strains for long-term storage. It maintained the population mixture of strains (9.4 × 108 cfu/ml) for 120 DAI followed by molasses (9.1 × 108 cfu/ml) and rice gruel (7.9 × 108 cfu/ml). These beneficial strains were further applied in field for crop productivity and slurry-based formulation with mixture of strains exhibited incredible plant growth after definite interval of time. Chemotactic activity proved these strains as strong root colonizers which was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM). This research disseminates a successful technology to develop an eco-friendly bioformulation of buffalo dung slurry augmenting the crop growth in an eco-friendly manner leading to sustainable agriculture.

Insights into zinc-sensing metalloregulator 'Zur' deciphering mechanism of zinc transportation in Bacillus spp. by modeling, simulation and molecular docking.

To comprehend the molecular mechanism of zinc transportation by bacteria tends to be a very complicated and time-consuming method. To date, fragmented and scanty studies are available about the mechanism of zinc transportation at molecular level. So, the present study scrutinizes in silico pathways of zinc fractions transportation, specifically in Bacillus spp. stimulating dynamic performance of zinc. For this, the constructed model reveals Zur to be the prime regulatory transport protein maintaining bacterial survivability at fluctuation in zinc concentrations, thereby attaining zinc homeostasis. Topology for hub nodes displays appropriate evidence of the molecular basis of bacterial zinc imports and exports. Further, the molecular docking reveals interaction of Zur protein with the zinc ligands (ZnCO3 and ZnSO4). By validation of binding affinity, binding energy and docking score via Autodock Vina and X-Score, the ZnSO4 compound was found to possess excellent stability in the active pocket site of Zur, stating Zur-ZnSO4 complex to be the most potential. Owing to which, the Zur-ZnSO4 complex was selected and subjected to molecular dynamics simulation, revealing RMSD, RG, RMSF, SASA and interaction energy for 20 ns trajectory period. Henceforth,the study provides novel insight into revealing the unrecognized Zur protein pathway, assisting zinc transportation, besides retaining best interaction with ZnSO4 ligand. This is the first system biology where molecular docking and molecular dynamics simulation-based investigation decipher the role of Zur transport protein system and interaction of its amino acids with zinc ligands in a simpler and economical form via in silico techniques.Communicated by Ramaswamy H. Sarma.

Next-generation biofertilizers and novel biostimulants: documentation and validation of mechanism of endophytic plant growth-promoting rhizobacteria in tomato.

A study was conducted to determine the suitability of the endophytes as probable next-generation biofertilizers and novel biostimulants. Enterobacter turicensis RCT5 and Stenotrophomonas maltophilia RCT31 showed a zone of solubilization, of phosphate, potassium, silicate, and zinc, produced phytase. Among the three media used for phosphate solubilization, the rhizospheric medium turned out to be the best-producing results in less than 24 h, while others took a longer time to give the same results. The strains exhibited differential ability to produce organic acids in the plate assay and eight of these were profuse producers of exopolysaccharides. We were able to partially elucidate the mechanism of solubilization of insoluble salts that included organic acids and protein activity in the cell-free culture filtrates of endophytes. All the root nodule endophytes showed potential as novel biostimulants and next-generation biofertilizers as found in the germination assay of tomato, a non-host crop using different methodologies. It proved that the endophytes have different mechanism of expressions of their plant growth-promoting traits as well as can promote the growth of tomato plant irrespective of the method used.

ACC deaminase-producing Ensifer adhaerens KS23 enhances proximate nutrient of Pisum sativum L. cultivated in high altitude.

A phytohormone producing, N2-fixing and 1-aminocyclopropane-1-carboxylate (ACC) deaminase synthesizing bacterium Ensifer adhaerens KS23 effectively increased the yield and nutritional contents of Pisum sativum var. Arkel. The isolate KS23 showed positive ACC deaminase activity with 174.2 (nmol of α-ketobutyrate/g-1 biomass½ h-1) a 9.7-fold increase in glutathione S-transferase activity. The proximate analysis exhibited an increased yield of protein (21.45%), carbohydrate (38.90%), sulphur (29.94%) starch (27.52%), total ash (35.57%), fat content (27.5%), nitrogen (24.06%) and hydrogen (17.91%) in treated seeds of P. sativum as compared to untreated crop seeds in field trials at Srikot village, Srinagar-246,174 (Garhwal) India. The most desirable essential and non-essential amino-acids content was also enhanced simultaneously by E. adhaerens KS23 as compared to non-treated crop seeds. This study revealed the enhancement of various nutritional contents resulting in quality improvement and an increase in growth productivity of pea. This study provides an encouraging result that may benefit the marginal income of farmers belonging mainly to hilly regions who are dependent on traditional methods of farming and thus improving their economy.

Bacillus megaterium Strain CDK25, a Novel Plant Growth Promoting Bacterium Enhances Proximate Chemical and Nutritional Composition of Capsicum annuum L.

The present study aimed to scrutinize the effect of different cow dung bacterial treatments on the nutritional value of Capsicum annuum L. Among all treatments, seeds inoculated with Bacillus megaterium (CDK25) showed significant enhancement in various proximate constituents viz., crude fiber (3.31%), crude protein (3.84%), and ash (2.53%) as compared to control. Likewise, significant increase in different nutrient contents viz., Ca (16.26 mg/100 g), Mg (17.37 mg/100 g), P (11.91 mg/100 g), K (0.47 mg/100 g), Fe (1.37 mg/100 g), and Zn (0.21 mg/100 g) was recorded over the control. Principal component analysis data depicts a positive correlation between different treatments with variables, validating enhancement in nutritional constituents by B. megaterium (CDK25) treatment. The study suggests the application of "B. megaterium" for achieving the persistent potential for augmenting and boosting up plant biological, functional, and nutritional assets, thereby enhancing the overall edible quality of C. annuum L. along with weathering of soil minerals.

Buffalo dung-inhabiting bacteria enhance the nutrient enrichment of soil and proximate contents of Foeniculum vulgare Mill.

The present study was aimed to study the effect of bacteria inhabiting in buffalo dung on nutritional properties of soil and plant. Three beneficial bacteria Proteus mirabilis, Pseudomonas aeruginosa, and Enterobacter xiangfangensis were isolated from buffalo dung to evaluate for their effects individually as well as in consortium. The combined effect of P. mirabilis and P. aeruginosa showed a significant enhancement in different biological parameters of Foeniculum vulgare such as primary branch (99.32%), secondary branch (98.32%), number of umbels (87.62%), number of umbellets (99.85%), number of seeds (104.94%), grain yield (62.38%), biological yield (35.99%), and harvest index (19.48%). Consortium of these potent bacteria also enhanced proximate constituents such as total ash (49.79%), ether extract (63.06%), crude fibre (48.91%), moisture content (33.40%), dry matter (31.45%), acid insoluble ash (33.20%), and crude protein (40.73%). A highly significant correlation (p ≤ 0.01) was found between nitrogen (r = 0.97), phosphorous (r = 0.95), and potassium (r = 0.97) contents of soil. This research enhances the knowledge of the effect of plant growth-promoting bacteria on nutrient properties of soil and fennel which deliver a new index for healthier use in organic agricultural practices.

Characterization of a plant-growth-promoting non-nodulating endophytic bacterium (Stenotrophomonas maltophilia) from the root nodules of Mucuna utilis var. capitata L. (Safed Kaunch).

Nonrhizobial root nodule endophytic bacteria are known to have beneficial effects on host plants and are also considered contaminants or opportunists. They grow either individually or as a co-occupant of the root nodules of legumes. In this study, a nonrhizobial endophytic bacterial strain was isolated from the root nodules of the medicinal legume Mucuna utilis var. capitata L.; phenotypic, genotypic, and agricultural characterization was performed using a HiMedia kit and 16S rRNA sequencing. This strain showed tremendous seedling growth potential (30%), compared with the control, as well as a strong antagonistic nature against the plant pathogenic fungus Fusarium udum when plant growth parameters were analyzed. The strain, identified by 16S rRNA as Stenotrophomonas maltophilia, showed a multitude of plant-growth-promoting attributes both direct (IAA, phosphate solubilization) and indirect (ACC deaminase, siderophore) and enhanced the growth of host plant in field trials. This is the first report of the plant-growth-promoting potential of this endophytic bacterium from the nodules of M. utilis var. capitata L.; hence, it has potential for use in various biotechnological applications in various industries.

Endophytic bacteria promote growth of the medicinal legume Clitoria ternatea L. by chemotactic activity.

Part of the native root nodule endophytic microflora referring to members of the genera Proteobacteria and Sphingobacteria were used to test their bioefficacy as seed biopriming. These were quantified for their plant growth promoting (PGP) attributes such as IAA production, P and K-solubilization and ACC deaminase production. Results showed that significantly highest IAA was produced by E. hormaechi RCT10. The highest P-solubilization was observed with S. maltophila RCT31 it was solubilizing all the substrate tri-calcium phosphate, di-calcium phosphate, and zinc phosphate. Significantly highest K-solubilization was observed with S. maltophila RCT31 followed by E. turicensis RCT5. However, the maximum zinc solubilization was reported with S. maltophila RCT31 followed by E. turicensis RCT5. The maximum ACC deaminase was quantified in the bacterium. Results revealed that the E. hormaechi RCT10 utilized seed leechates most effectively while root exudates were maximally utilized by S. maltophila RCT31. The pots experiment proves that S. maltophila RCT31 was the most effective bacterium and it was replication vis-à-vis field experiment. In particular, S. maltophila RCT31 holds strong potential to be possibly used as a bioformulation for the medicinal legume, as an economical and eco-friendly alternative to agrochemicals.

Zinc solubilizing bacteria (Bacillus megaterium) with multifarious plant growth promoting activities alleviates growth in Capsicum annuum L.

The present study was designed to isolate an array of zinc solubilizing bacteria (ZSB) and to characterize them for plant growth promotion (PGP) attributes with respect to Capsicum annuum L. For this purpose, seventy bacteria were procured from cow dung and screened for zinc solubilization (ZnO and ZnCO3). Where, isolate CDK25 was found to be the most potent owing to its maximum zinc solubilization (ZnO) ability (5.0 cm). For quantitative assay, atomic absorption spectroscopy (AAS) was used, where CDK25 showed markedly higher solubilization of ZnO (20.33 ppm). It was investigated that CDK25 also endowed with multiple PGP attributes viz., Phosphate solubilization, Phytase production, Indole acetic acid (IAA) and Siderophore production. Quantitative study revealed isolate CDK25 to solubilize and produce maximum quantity of phosphate (281.59 µg/ml) and IAA (13.8 µg/ml) respectively. ZSB was applied in different treatments under pot culture assay, where T3 (seeds + CDK25) showed significant impact on plant growth parameters, besides showing maximum zinc content in fruit (0.25 mg/100 g). Hence, isolate CDK25 expresses highest potential throughout the experiments; as zinc solubilizer, PGP strain, and based on 16S rRNA gene sequencing identified as Bacillus megaterium. Therefore, meticulous use of this bacterium could aid in providing adequate amount of soluble zinc along with enhanced plants growth, nutrient uptake and yield in sustainable manner.

Combined effects of rhizo-competitive rhizosphere and non-rhizosphere Bacillus in plant growth promotion and yield improvement of Eleusine coracana (Ragi).

This study emphasizes the beneficial role of rhizo-competitive Bacillus spp. isolated from rhizospheric and non-rhizospheric soil in plant growth promotion and yield improvement via nitrogen fixation and biocontrol of Sclerotium rolfsii causing foot rot disease in Eleusine coracana (Ragi). The selection of potent rhizobacteria was based on plant-growth-promoting attributes using Venn set diagram and Bonitur scale. Bacillus pumilus MSTA8 and Bacillus amyloliquefaciens MSTD26 were selected because they were effective in root colonization, rhizosphere competence, and biofilm formation using root exudates of E. coracana L. rich with carbohydrates, proteins, and amino acids. The relative chemotaxis index of the isolates expressed the invasive behavior of the rhizosphere. During pot and field trials, the consortium of the rhizobacteria in a vermiculite carrier increased the grain yield by 37.87%, with a significant harvest index of 16.45. Soil analysis after the field trial revealed soil reclamation potentials to manage soil nutrition and fertility. Both indexes ensured crop protection and production in eco-safe ways and herald commercialization of Bacillus bio-inoculant for improvement in crop production and disease management of E. coracana.

Revisiting the plant growth-promoting rhizobacteria: lessons from the past and objectives for the future.

Plant beneficial rhizobacteria (PBR) is a group of naturally occurring rhizospheric microbes that enhance nutrient availability and induce biotic and abiotic stress tolerance through a wide array of mechanisms to enhance agricultural sustainability. Application of PBR has the potential to reduce worldwide requirement of agricultural chemicals and improve agro-ecological sustainability. The PBR exert their beneficial effects in three major ways; (1) fix atmospheric nitrogen and synthesize specific compounds to promote plant growth, (2) solubilize essential mineral nutrients in soils for plant uptake, and (3) produce antimicrobial substances and induce systemic resistance in host plants to protect them from biotic and abiotic stresses. Application of PBR as suitable inoculants appears to be a viable alternative technology to synthetic fertilizers and pesticides. Furthermore, PBR enhance nutrient and water use efficiency, influence dynamics of mineral recycling, and tolerance of plants to other environmental stresses by improving health of soils. This report provides comprehensive reviews and discusses beneficial effects of PBR on plant and soil health. Considering their multitude of functions to improve plant and soil health, we propose to call the plant growth-promoting bacteria (PGPR) as PBR.

Decoding multifarious role of cow dung bacteria in mobilization of zinc fractions along with growth promotion of C. annuum L.

Zinc is one of the micronutrients, required by all types of crops. About 10-100ppm of zinc is present in soil which is generally immobile. The cow dung sustains all life and being practice since aeons. Exploitation of cow dung bacteria can mobilize nutrients besides contributing in sustainable agriculture. Therefore, to examine mobilization of Zn, cow dung is used as a source of bacteria. The objectives of the present study were to isolate an array of bacteria from cow dung and to characterize them for their Zn (ZnO and ZnCO3) mobilization ability in addition to establish the optimum conditions for dissolution of zinc. A total of seventy bacterial isolates have been screened for Zn mobilization. Out of which most potent (CDK15 and CDK25) were selected to study the effect of various parameters viz. pH, temperature and concentration of Zn. These parameters were assessed qualitatively in diverse growth medium and quantitatively using Atomic absorption spectroscopy. Optimum pH and temperature for mobilization was recorded at pH 5 (ZnO) and 37 °C (ZnCO3) by CDK25, whereas, optimum zinc concentration for mobilization was recorded at 0.05% (ZnO) by CDK15. Maximum amount of Zn solubilized was recorded by CDK25 in ZnO (20ppm). Considering the abilities of most potent bacterial isolates with reference to P-mobilization and growth promoting traits, pot culture assay of C. annuum L. was carried out. The findings of which conclude that, bacterium CDK25 (Bacillus megaterium) could be exploited for factors viz. nutrient management of Zn, growth promoting agent, and Zn augmentation in soil.

Sulfur-oxidizing buffalo dung bacteria enhance growth and yield of Foeniculum vulgare Mill.

This study aimed to harness the benefits of sulfur-oxidizing beneficial bacteria from buffalo dung to improve crop yields of Foeniculum vulgare. A total of 61 bacterial isolates were screened from buffalo dung, of which 40 isolates exhibited plant-growth-promoting attributes, such as phosphate solubilization, indole-3-acetic acid production, and hydrogen cyanide production. Of these 40, four bacterial isolates, viz., BUFF12, BUFF14, BUFF23, and BUFF38, were the most potent, having plant-growth-promoting and sulfur-oxidizing properties. These four isolates produced phytase by solubilizing calcium phytate and sodium phytate. They solubilized potassium besides oxidizing the sulfur, causing an increase in soil fertility and crop production. All four isolates were nonpathogenic in nature, as demonstrated by a negative haemolysis test. According to the 16S rRNA gene sequence, the isolate BUFF14 was identified as Proteus mirabilis. Proteus mirabilis BUFF14 maximized seed germination with enhanced vegetative and reproductive parameters during pot and field trial studies, compared with the other isolates.

Roles of quorum sensing molecules from Rhizobium etli RT1 in bacterial motility and biofilm formation

ABSTRACT Strain RT1 was isolated from root nodules of Lens culinaris (a lentil) and characterized as Rhizobium etli (a Gram-negative soil-borne bacterium) by 16S rDNA sequencing and phylogenetic analysis. The signaling molecules produced by R. etli (RT1) were detected and identified by high-performance liquid chromatography coupled with mass spectrometry. The most abundant and biologically active N-acyl homoserine lactone molecules (3-oxo-C8-HSL and 3-OH-C14-HSL) were detected in the ethyl acetate extract of RT1. The biological role of 3-oxo-C8-HSL was evaluated in RT1. Bacterial motility and biofilm formation were affected or modified on increasing concentrations of 3-oxo-C8-HSL. Results confirmed the existence of cell communication in RT1 mediated by 3-oxo-C8-HSL, and positive correlations were found among quorum sensing, motility and biofilm formation in RT1.

Differential antagonistic responses of Bacillus pumilus MSUA3 against Rhizoctonia solani and Fusarium oxysporum causing fungal diseases in Fagopyrum esculentum Moench.

Chitinase and surfactin-mediated biocontrol of Rhizoctonia solani and Fusarium oxysporum causing wilt and root rot of Fagopyrum esculentum respectively has been studied in this communication. Bacillus pumilus MSUA3 as a potential bacterial strain strongly inhibited the growth of R. solani and F. oxysporum involving the chitinolytic enzymes and an antibiotic surfactin. Plant growth promoting attributes seem to be involved in plant growth promotion and yield attributes. The action of cell-free culture supernatant (CFCS) was found deleterious to F. oxysporum and R. solani even in the heat-treated (boiled/autoclaved) CFCS. The possible involvement of surfactin in disease control was revealed by colony PCR amplification of SrfA. Chitinolytic enzyme and antibiotic surfactin evidenced differential biocontrol of F. oxysporum and R. solani by B. pumilus MSUA3. A significant reduction in disease index under gnotobiotic conditions and productivity enhancement of F. esculentum using vermiculite-based bioformulation revealed B. pumilus MSUA3 as a successful potential biocontrol agent (BCA) and an efficient plant growth promoting rhizobacterium (PGPR) for disease management and productivity enhancement of buckwheat crop.

Roles of quorum sensing molecules from Rhizobium etli RT1 in bacterial motility and biofilm formation.

Strain RT1 was isolated from root nodules of Lens culinaris (a lentil) and characterized as Rhizobium etli (a Gram-negative soil-borne bacterium) by 16S rDNA sequencing and phylogenetic analysis. The signaling molecules produced by R. etli (RT1) were detected and identified by high-performance liquid chromatography coupled with mass spectrometry. The most abundant and biologically active N-acyl homoserine lactone molecules (3-oxo-C8-HSL and 3-OH-C14-HSL) were detected in the ethyl acetate extract of RT1. The biological role of 3-oxo-C8-HSL was evaluated in RT1. Bacterial motility and biofilm formation were affected or modified on increasing concentrations of 3-oxo-C8-HSL. Results confirmed the existence of cell communication in RT1 mediated by 3-oxo-C8-HSL, and positive correlations were found among quorum sensing, motility and biofilm formation in RT1.